1. Field of Invention
This invention pertains to a public address system, and more particularly to a public address system especially useful in locations, wherein echoes, acoustic resonance and large spaces hamper the transmission of audio signals from regular speakers.
2. Description of the Prior Art
Public address systems are frequently used in various public places including subway stations, railway stations, tunnels, airports, and so on, for making announcements and/or playing background music. Most of these systems include a plurality of speakers which are substantially used as point sound sources. These locations have generally very large volumes, including high ceilings, and poor acoustic characteristics so that the audio signals emitted by the speakers are dissipated in undesirable directions and are echoed so that they frequently become unintelligible. Furthermore, if these speakers are exposed they can be subjected to unauthorized tampering and even vandalism.